Technical Field
The present invention pertains generally to the field of materials and devices for thermoelectric energy conversion including methods of producing the same.
Background
Thermoelectric materials are a class of materials that can efficiently convert between thermal energy and electrical energy. Only certain materials have been found usable with this property. Thermoelectric (TE) materials are useful in many applications. With TE materials, electricity can be employed to dissipate heat (thermoelectric coolers) or waste heat can be utilized to generate electricity (thermoelectric generators). Additionally TE devices have the advantage of no moving parts and thus are quiet, requiring little maintenance. Therefore, TE materials are useful in a wide variety of general applications such as refrigeration and power generation as well as niche applications such as cooling IR sensors, laser diodes and computer electronics, and powering space probes. However, the TE properties of these devices have been insufficient for broader application such as absorption chillers, which capture waste heat and then recycle the waste heat for industrial refrigeration. The low efficiency of TE devices is due to a low value of the basic materials' figure-of-merit, ZT. Typical state-of-the-art commercial TE materials can only achieve a ZT value of around 1. However, a conventional chiller or a waste heat recovery device might require a ZT of 2-3 for practical applications.
Thus, there is a great need for thin film flexible thermoelectric energy harvesting and conversion devices that can be used, for instance, to power wearable electronics using body heat or to convert heat waste produced by machinery, brakes, heat sinks, and other devices into electricity.